JP2002344560A - Mobile communication terminal - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a mobile communication terminal capable of performing data communication at an optimum error rate and an optimum data communication speed according to the state of downlink data. A terminal predicts a downlink data communication speed based on a reception state of a signal from a base station in a terminal, and notifies the base station of the predicted downlink data communication speed,
When the base station communicates data at the predicted downlink data communication rate, the status acquisition means (CP) acquires the status of downlink data.
U) 9, one or more tables 13a provided for use in predicting the predicted downlink data communication speed, and in advance, storing the signal reception state and the downlink data communication speed in association with each other and corresponding to the downlink data status. Selecting means (CIR-D) for selecting a corresponding table in accordance with the result of acquisition by the CPU 9.
An RC conversion unit 13 and a notifying unit (CPU) 9 for notifying the base station of a predicted downlink data communication rate based on the table selected by the selecting unit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for predicting a downlink data communication rate on the terminal side based on a reception state of a signal from a base station in the terminal and notifying the predicted downlink data communication rate to the base station. The present invention relates to a mobile communication terminal adopting a data communication method in which a base station communicates data at a predicted downlink data communication speed.

[0002]

2. Description of the Related Art In recent years, as a next-generation high-speed wireless communication system,
cdma2000 1x-EV DO method has been developed. Cdma200 above
0 1x-EV DO system is a standardized version of the HDR (High Data Rate) system, which is an extension of cdma2000 1x by Qualcomm, and is based on Std.T-64 1S-2000 by ARIB.
CS0024 “cdma2000 High Rate Packet Data Air Inte
rface Specification ", which is currently being serviced by KDDI in Japan. The cdmaOne method (ARIB T-53 in Japan, EIA / TIA / IS-95 in North America, Korea, etc.)
Etc.) and expanded to support 3rd generation (3G) cdma
This is a method aimed at improving the communication speed by further specializing the 2000 1x method to data communication. Cdma2000 l
In x-EV DO, EV stands for Evolution, and DO stands for Data only.

In the cdma2000 1x-EV DO system, the base station switches the modulation scheme of data transmitted to the terminal based on information notifying the reception state received from the mobile communication terminal, so that the reception state of the terminal is changed. It is possible to use a communication rate with low error resilience but high speed when good, and a communication rate with low error but high error resilience when reception condition is bad. In this method, the downlink data communication speed is
Rather than simply being determined by the instantaneous value of the CIR (carrier-to-interference ratio) indicating the reception state as in the conventional cdmaOne system, it is corrected by prediction and correction of statistical data such as the error rate of past downlink data transmission. Change. That is, cdma2000 1x-EV D
Since the change in data communication speed depending on the location is not so remarkable as in the O method, the judgment of the reception state and the like is also made by Ec / Io (pilot signal strength versus total received signal strength) obtained from the pilot signal received from the base station. , CIR and the like.

On the other hand, the cdma2000 1x-EV DO system directly shows an extremely accurate data communication rate obtained in consideration of prediction and correction based on statistical data such as an error rate of past downlink data transmission. Estimated downlink data communication speed (D
The terminal side is provided with a RC (Data Rate Control Bit) as a table, and based on this table, the terminal notifies the base station of the predicted downlink data communication speed. Thus, data communication at the various communication rates described above is performed.

In the cdma2000 1x-EV DO system, in the downlink direction (direction from the base station to the mobile communication terminal), the time is set to 1/60.
Time-division multiplexing access, in which the communication is performed with only one mobile communication terminal within that time and communication with a plurality of mobile communication terminals is performed by switching the communication partner mobile communication terminal according to time during that time, TDMA; time division multip
lex access). Thus, data transmission can be always performed with the maximum power to each mobile communication terminal, and data communication performed between the mobile communication terminals can be performed at the highest communication speed.

As described above, the above-mentioned cdma2000 1x-EV DO
The method has a characteristic that the data communication speed in the direction from the base station to the portable communication terminal greatly changes depending on the reception state (for example, received electric field strength, carrier-to-interference ratio = CIR) in the portable communication terminal. For example, when the mobile communication terminal has the best reception condition, data communication at a communication speed of 2.4 Mbps is possible.
The data communication speed will be reduced to about 10 kbps.

[0007] In the cdma2000 1x-EV DO system, the data communication speed is determined so that the error rate is always 1% or less in each reception state of the portable communication terminal.

[0008]

However, when the data communication rate is set such that the error rate of the downlink data is 1% or less, the optimum error rate and the data communication rate are determined according to the state of the downlink data. There was a problem that the speed could not be selected.

For example, when the downlink data is streaming data based on the UDP / IP protocol, the error rate may be 1% or more, but it is required to increase the communication speed. If the downstream data is data relating to an online game, the communication speed may be low, but the error rate may be one.
% Or less to avoid delay due to data retransmission.

[0010] The present invention has been made in view of such circumstances, and performs data communication at an optimum error rate and data communication speed according to the state of downlink data and the state of a terminal at the time of downlink data reproduction. It is an object of the present invention to provide a mobile communication terminal capable of performing the following.

[0011]

In order to achieve the above object, a portable communication terminal according to the present invention predicts a downlink data communication speed on a terminal side based on a reception state of a signal from a base station in the terminal. By notifying the predicted downlink data communication rate to the base station, the base station employs a data communication method for communicating data at the predicted downlink data communication rate, and the state of the downlink data or the downlink data reproduction. State acquisition means for acquiring the state of the terminal at the time, and used for prediction of the predicted downlink data communication rate, and storing the signal reception state and the downlink data communication rate in association with each other in advance, and the state of the downlink data or One or more tables provided corresponding to the state of the terminal, and a selection unit that selects a corresponding table according to an acquisition result of the state acquisition unit; A predicted downlink data rate based on the serial selection means selects a table, characterized by comprising a notification unit for notifying to the base station. With this configuration, a table is prepared in accordance with the state of the downlink data such as the type of the content or the state of the terminal at the time of reproducing the downlink data, and the communication speed is determined based on this table. Reception can be performed in an optimal reception environment (error rate, communication speed) according to the state of downlink data and the like.

The portable communication terminal according to claim 2, wherein said data communication method is adopted, and said state acquisition means for acquiring a state of said downlink data or a state of said terminal when said downlink data is reproduced; Used for estimating the communication speed, a table for storing the signal reception state and the downlink data communication speed in association with each other in advance, and according to the acquisition result of the state acquisition unit, the signal reception state for referring to the table, Or a numerical value changing means for changing a numerical value of the downlink data communication rate based on the table, and a notifying means for notifying the base station of a predicted downlink data communication rate based on the numerical value changed by the numerical value changing means. It is characterized by. According to this configuration, a predicted CIR value (signal receiving state) for referring to the table or a DRC value (downlink data communication speed) based on the table according to the state of the downlink data or the state of the terminal at the time of downlink data reproduction. ), The predicted data communication speed is determined according to the numerical value after the change, so that the user can receive in an optimal reception environment according to the state of the downlink data.

The portable communication terminal according to claim 3, wherein the status acquisition means includes a communication protocol for the downlink data,
It is characterized by acquiring a type of the downlink data or an application for reproducing the downlink data.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration of a portable communication terminal adopting the cdma2000 1x-EV DO system according to an embodiment of the present invention. As shown in FIG. 1, the mobile communication terminal according to the present embodiment includes an RF unit including an antenna 1, a duplexer 3, a demodulator 5, and a modulator 19, a decoder 7, and a predictor 1.
1. CIR-DRC converter (selecting means, numerical value changing means) 13 for storing a table to be described later, multiplexer (M
UX; Multiplexer) 15, a CPU (status acquisition unit, notification unit) 9, a memory 21 for storing various information including application software described later, a display unit 23 including a liquid crystal display, a keypad, An operation unit 25 such as a keyboard is provided. Also,
An external interface (for example, serial port, parallel port, USB, blue-tooth, infrared communication, 10base-T LAN) with a personal computer (PC) 29 so that the mobile communication terminal can be used as a wireless modem.
Etc.) 27.

<< Outline of Operation of Portable Communication Terminal Adopting cdma2000 1x-EV DO System >> Next, an outline of operation of the cdma2000 1x-EV DO system for the portable communication terminal having the above configuration will be described. The downlink pilot signal from the base station received by the mobile communication terminal is demodulated by the demodulator 5 via the antenna 1 and the duplexer 3. At this time, the demodulator 5
Demodulates a multiplexed signal from a baseband received signal by a demodulation method corresponding to the modulation method of the received signal received from the base station. In this embodiment, Q
PSK (quadriphase phase shift keying), 8PSK
(8 phase shift keying), 16QAM (16 amplit
ude modulation).

The received data demodulated by the demodulator 5 is output to the decoder 7 and decoded by the decoder 7. That is, the spectrum-spread received multiplexed signal is spectrum-spread. Here, if there is received data (for example, a call signal from a call partner or data that is desired to be downloaded) assigned to the own station, the received data is output from the decoder 7 to the CPU 9. This received data is processed in the CPU 9 or
External P via U9 and external interface 27
It is sent to C etc. 29. Further, in the course of the decoding process, the decoder 7 calculates Ec / Io (pilot signal strength versus total received signal strength) and calculates CIR (carrier to interference ratio) based on the following equation (1). CIR = (Ec / lo) / (1-Ec / lo) ... (1)

The CIR determined based on the above equation is
The signal is output from the decoder 7 to the predictor 11, where the next reception slot timing (here, one slot is
The value of CIR at 1.66 ms = 1/600 second) is predicted. The method of prediction here is not particularly limited, but a method such as linear prediction is exemplified. In addition, the predictor 1
Information indicating how many CIRs should be predicted after 1 is included in various control signals transmitted from the base station when the power of the mobile communication terminal is turned on. Then, the predicted CIR obtained by the predictor 11 is output to the subsequent CIR-DRC converter 13.

The CIR-DRC converter 13 has a (CIR-DRC conversion) table shown in FIG. 2, and converts a predicted CIR into a DRC based on this table. This DR
C is the highest communication speed expected from the predicted CIR and receivable by the portable communication terminal at a predetermined error rate or less. Here, as shown in FIG. 2, the DRC corresponding to the reference CIR is defined in the CIR-DRC conversion table. When the input predicted CIR is the reference CIR, the CIR-DRC conversion unit 13 outputs a DRC corresponding to the reference CIR to the CPU 9. On the other hand, predictor 1
If the input predicted CIR is not the reference CIR, the DRC corresponding to the reference CIR closest to the input predicted CIR is obtained, or the input predicted CIR is obtained.
By interpolating from the binary CIR closest to the IR,
The DRC corresponding to the interpolated CIR is obtained. As a result, it is possible to acquire a DRC corresponding to each predicted CIR, and it is possible to notify the base station of a more accurate reception state.

The DRC obtained as described above is CI
Output from the R-DRC converter 13 to the CPU 9. DR
When C is input, the CPU 9 determines whether there is transmission data generated in the mobile communication terminal or input from an external PC or the like 29 via the external interface 27. Then, when there is transmission data, the CPU 9 outputs the transmission data to the multiplexer 15 together with the DRC described above. On the other hand, when there is no transmission data, the DRC input from the CIR-DRC converter 13 is converted to a multiplexer (MUX; Multiplexer) 1.
Output to 5

The DRC and transmission data output from the CPU 9 are multiplexed by the multiplexer 15, further encoded by the encoder 17, modulated by the modulator 19 by a specific modulation method (for example, QPSK), and 3 and transmitted to the base station via the antenna 1.
The base station determines, based on the DRC received from each mobile communication terminal, to which mobile communication terminal the next slot will be used for transmission, and the communication speed (and modulation scheme) for the transmission.

<< First Embodiment >> Next, the operation of the portable communication terminal according to the first embodiment of the present invention will be described.
In the first embodiment of the present invention, the above-mentioned CIR-DRC
When the conversion unit 13 converts the predicted CIR into the DRC, it is characterized in that it refers not only to the standard table shown in FIG. 2 but also to another table shown in FIG. Hereinafter, the conversion process to DRC will be described with reference to the flowchart of FIG.

In FIG. 4, first, the CPU 9 acquires the type of downlink data (content) as the state of downlink data (step S100). As an acquisition method, for example, when the terminal specifies content to be downloaded and transmits the content to the base station, the type of the content (category or the like) may be input. Alternatively, attribute information of the content may be recorded in the content header portion, and when the content starts to be downloaded, the header information may be obtained on the terminal side. The CPU 9 outputs the obtained type to the CIR-DRC converter 13.

Next, the CIR-DRC converter 13 selects a table corresponding to the type (step S11).
0). The CIR-DRC conversion unit 13 includes a plurality of tables 13a including the table of FIG. 3 in addition to the standard table of FIG. 2, and selects a desired table from these tables.

Here, the standard table of FIG. 2 usually depends on the CIR value in the left column, although it also depends on the system design.
The communication speed at which data communication can be performed with an error rate of not more than% is defined as the DRC value. Then, the value increases from the top of the table to the bottom.

On the other hand, the table in FIG. 3 is provided according to the type (category) of the streaming content. For example, a table for the type of content in which the image moves rapidly (FIG. 3A) and a table for the image (See FIG. 3B) for content of a type having a small number of contents. For example, if the content category is “soccer”, C
The IR-DRC converter 13 determines that the content is a rapidly moving content, and selects the table shown in FIG.

In the table of FIG. 3A, C in the left column
In the IR value, the CIR value (C
Data is arranged in order from the CIR value (Ci0) having a smaller value than i1). On the other hand, the DRC values in the right column are the same as those in the standard table shown in FIG. That is, even if the CIR value is smaller than that of the standard table, the DR
The C value is output. Therefore, FIG.
In the table of (a), settings are made such that high-speed communication is performed even when the reception state is poor. Therefore, as in the case of streaming of a soccer game, a high communication speed is required due to intense movement, In the case where some noise does not become a problem due to the intensity of the error, the error rate can be increased (for example, 3%) and the communication speed can be increased.

On the other hand, in the table of FIG. 3B, in the CIR values in the left column, data is arranged in order from the CIR value (Ci2) having a larger value than the CIR value (Ci1) in the standard table of FIG. And the largest C
Ci11 is adopted as the IR value. On the other hand, the DRC values in the right column are the same as those in the standard table shown in FIG. That is, even if the CIR value is larger than that of the standard table, a DRC value equivalent to the CIR value is output. Therefore, in the table shown in FIG. 3B, a setting is made such that the reception state is good and communication is performed at a relatively low speed. Therefore, as in the streaming of a news program, the communication speed needs to be high because of little movement. On the other hand, when noise is conspicuous due to little movement, the error rate is reduced (for example, 0.5
%) To make the communication speed relatively low.

After selecting a table as described above,
The CIR-DRC conversion unit 13 refers to this table and acquires a DRC at a predetermined CIR value by the above-described method (Step S120). Then, the CIR-DRC converter 13 outputs the acquired DRC to the CPU 9.

When the DRC is input, the CPU 9 appropriately converts the transmission data and the DRC into the multiplexer 1 by the method described above.
5, and the information is transmitted (notified) to the base station via the multiplexer 15, the encoder 17, and the modulator 19, and via the duplexer 3 and the antenna 1 (step S).
130). The base station determines the communication speed based on the DRC, and the terminal receives the downlink data (content) at the optimum error rate and communication speed (step S140).

As described above, a table is prepared in accordance with the state of the downlink data such as the type of the content, and the communication speed is determined based on this table. Reception can be performed in a reception environment (error rate, communication speed).

<< Second Embodiment >> Next, the operation of the portable communication terminal according to the second embodiment of the present invention will be described.
In the second embodiment, the above-described CIR-DRC converter 1
3 uses the standard table shown in FIG.
When converting to RC, a numerical value is changed by applying a predetermined offset. Hereinafter, the conversion process to DRC will be described with reference to the flowchart of FIG.

In FIG. 5, steps S200, S23
0 and 240 correspond to steps S100 and S13 in FIG.
Since these are the same as 0 and 140, respectively, the description is omitted.
Then, the CIR-DRC conversion unit 13 determines
A predetermined offset is applied to the predicted CIR value for referring to the standard table in FIG. 2 (step S210), and the DRC is acquired by referring to the table based on the predicted CIR value by the above-described method (step S220).

FIG. 6 shows a mode in which the predicted CIR value is offset and the table is referred to. For example, prediction C
When the IR value is Ci5, normally, Dr5 corresponding to the IR value is obtained as the DRC value. On the other hand, if the content category is “soccer”, as in the first embodiment, the CIR-DRC conversion unit 13 determines that the content is a fast-moving content and applies a positive offset amount to Ci5. Has become. Thereby, the CIR value becomes Ci4
Since the obtained DRC value is Dr6, it is possible to perform communication at a high communication speed with a high error rate.

If the content is a "news program", as in the first embodiment, the CIR-DRC converter 13 determines that the content is a content with little movement, and
Is applied with a negative offset amount. As a result, the CIR value becomes a value equivalent to Ci6, so that the obtained DRC value becomes Dr4, and communication can be performed with a low communication rate but a low error rate.

As described above, according to the state of the downlink data such as the type of the content, the prediction C for referring to the table is determined.
By changing the value of the IR value (signal reception state), the communication speed is determined according to the value after the change. Therefore, the user can optimize the reception environment (error rate, communication speed, etc.) according to the state of the downlink data. ) Can be received.

Although the embodiments of the present invention have been described in detail with reference to the drawings, the specific configuration is not limited to the embodiments, and includes a design and the like without departing from the gist of the present invention. It is. For example, in each of the above embodiments, the types of the downlink data (soccer,
(A category of a news program or the like), but the type of an application used when the downlink data is reproduced on the terminal side may be obtained. For example, if the downstream data is streaming which is a moving image, a moving image reproducing player is started as an application for reproducing the moving image, and if it is a still image, a predetermined still image reproducing player is started. Can be. Then, according to the application, the table may be changed as in FIG. 3 or a predetermined offset may be applied as shown in FIG.

Further, a communication protocol for downlink data may be obtained. For example, the UDP / IP protocol is a connectionless type, and downlink data communicated by this protocol tends to allow a relatively high error rate. Therefore, if the communication protocol of the downlink data is UDP / IP, a table having a high error rate but a high communication speed may be selected or a positive offset may be applied to the predicted CIR value. On the other hand, in the case of the TCP / IP protocol, the reverse operation may be performed.

As a method of acquiring the communication protocol, the terminal itself reads "http" from address information used when the terminal specifies content to be downloaded, for example, "http://www.xxx", and The communication method (in this case, equivalent to the TCP / IP protocol) may be obtained based on the communication method. Alternatively, protocol information may be recorded in a predetermined area such as a header of downlink data, and this information may be acquired by the terminal at the time of downloading. Further, in the second embodiment, the DRC is obtained by referring to the standard table from a value obtained by multiplying the predicted CIR value by a predetermined offset.
The DRC may be acquired by referring to the standard table without applying an offset to the R value, and the acquired DRC value may be offset. In the table used in the first embodiment, the predicted CIR value of the standard table is changed, but the DRC value may be changed.

[0039]

As described above, according to the first aspect of the present invention, a table is prepared according to the state of downlink data such as the type of content or the state of the terminal at the time of downlink data reproduction. Since the communication speed is determined based on this table, the user can receive in an optimal reception environment (error rate, communication speed) according to the state of downlink data and the like.

According to the second aspect of the present invention, a predicted CIR value (signal receiving state) for referring to a table or a table according to a state of downlink data or a state of the terminal at the time of downlink data reproduction. By varying the DRC value (downlink data communication speed) based on the above, the predicted data communication speed is determined according to the value after the change, so that the user receives in an optimal reception environment according to the state of the downlink data. be able to.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a schematic configuration of a mobile communication terminal according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of a CIR-DRC conversion table (standard table).

FIG. 3 shows a CIR-DR according to the first embodiment of the present invention.
It is a figure showing an example of a C conversion table.

FIG. 4 is a diagram showing a processing flow for converting a predicted CIR into a DRC.

FIG. 5 is another diagram showing a processing flow for converting a predicted CIR into a DRC.

FIG. 6 is a diagram showing a mode in which a predicted CIR value is offset and a table is referred to.

[Explanation of symbols]

1 ... antenna, 3 ... shared device, 5 ... demodulator, 7 ... decoder,
9: CPU (state acquisition unit, notification unit), 11: predictor, 13: CIR-DRC conversion unit (selection unit, numerical value variation unit), 13a: table, 15: MUX (multiplexer), 17: encoder, 19 modulator, 21 memory, 23 display unit, 25 operation unit, 27 external I / F
(Interface), 29 ... PC etc.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5K034 AA05 DD01 EE03 HH01 HH02 MM08 5K067 AA01 BB04 BB21 DD43 DD46 EE02 EE10 FF16 KK13 KK15

Claims (3)

[Claims] The terminal predicts a downlink data communication speed on the terminal side based on a reception state of a signal from a base station in the terminal, and notifies the base station of the predicted downlink data communication speed, so that the base station can In a portable communication terminal adopting a data communication method of communicating data at a predicted downlink data communication rate, a state acquisition means for acquiring a state of the downlink data, or a state of the terminal at the time of reproducing the downlink data, and the predicted downlink data For predicting the communication speed, the signal reception state and the downlink data communication speed are stored in association with each other in advance, and one or more tables provided corresponding to the downlink data state or the terminal state, Selecting means for selecting a corresponding table according to the result obtained by the state obtaining means; and predictive downlink data based on the table selected by the selecting means. And a notifying unit for notifying the base station of the data communication speed. 2. The base station predicts a downlink data communication rate on the terminal side based on a reception state of a signal from the base station in the terminal, and notifies the base station of the predicted downlink data communication rate. In a portable communication terminal adopting a data communication method of communicating data at a predicted downlink data communication rate, a state acquisition means for acquiring a state of the downlink data, or a state of the terminal at the time of reproducing the downlink data, and the predicted downlink data Used for estimating the communication speed, a table for storing the signal reception state and the downlink data communication speed in association with each other in advance, and according to the acquisition result of the state acquisition unit, the reception state of the signal for referring to the table, Or a numerical value changing means for changing the numerical value of the downlink data communication speed based on the table, and a number changed by the numerical value changing means. Notifying means for notifying the base station of a predicted downlink data communication rate based on a value. 3. The apparatus according to claim 1, wherein the status acquisition unit acquires a communication protocol of the downlink data, a type of the downlink data, or a type of an application for reproducing the downlink data. Mobile communication terminal.